Y. Li1, H. Wasik3, J. Motter2, D. Segev2, A. Massie2 1Johns Hopkins Bloomberg School of Public Health,Epidemiology,Baltimore, MD, USA 2Johns Hopkins University School Of Medicine,Surgery,Baltimore, MD, USA 3SUNY Upstate Medical University,Pediatric Nephrology,Syracuse, NY, USA
Introduction:
Significant weight gain after kidney transplantation (KT) is a risk factor for morbidity and mortality in adult populations. Many pediatric recipients experience a disproportionate increase in weight compared to height after KT. Understanding whether this accelerated weight gain confers increased risks of adverse outcomes would provide valuable guidance to posttransplant care for pediatric KT recipients.
Methods:
Using national registry data (SRTR), we studied 5646 first-time KT recipients 2004-2017 aged 2-18y at transplant with no prior history of diabetes. We calculated BMI-for-sex-height-age (BMI) percentile as a measure of adiposity using CDC growth charts. Posttransplant weight gain was defined as the absolute change in BMI% in the first year following KT, where BMI% is the percentage difference from the median BMI. In other words, this measures weight gain beyond expected changes due to height increase. New onset of diabetes after transplant (NODAT) was assessed during annual study visits after KT. We compared the cumulative incidence of patient death, all-cause graft failure, and NODAT across weight gain tertiles using inverse probability weighting and estimated the hazard ratios using adjusted Cox models.
Results:
Median (IQR) change in BMI% in the first year after KT was 7% (-1%, 16%), with patients who were underweight at KT showing the greatest increase (median: 13%) and patients who were obese showing the lowest increase (median: 3%). Patients in the highest tertile of posttransplant weight gain had a higher mortality during follow-up; there was no difference in the cumulative incidence of graft failure across weight gain tertiles (Figure). After adjusting for obesity status at KT and other known risk factors, the highest weight gain tertile (BMI% increase >12%) was associated with a 0.96 1.54 2.47-fold higher risk of death compared to the lowest tertile (BMI% increase <2% or weight loss). Among patients who were obese at KT (n=1070), posttransplant weight gain was an independent risk factor for NODAT (aHR: 1.05 1.70 2.74).
Conclusion:
Greater weight gain during the first year after pediatric KT was associated with an increased risk of NODAT among obese children. Posttransplant weight gain was positively associated with patient death with a borderline significance but not associated with graft failure in pediatric KT recipients. Close monitoring of weight gain in pediatric patients following KT may improve outcomes. Effects of interventions to prevent excess weight gain after pediatric KT requires further investigation.
